I missed out on G1 and Transformers in general when it was first aired. I began watching it in about 2007 on DVD.
I think the G1 cartoon is very funny. The way that the characters act on the show, some of the (bad) storylines, and the way that they have the "good" Autobots and "evil" Decepticons so clearly marked out where the Autobots always win in the end, well, yeah, I've just got to find it funny. Of course, it was G1 that set the standard for the general theme of Transformers (as well as many of the characters) used in all subsequent shows and movies of the franchise.
Despite all its flaws however, the cartoon is still highly enjoyable to watch. It's the original, "grass roots" continuity of Transformers that helped kick off the huge, long-running and ever changing franchise that it is today.
Recommended viewing? For already established newer fans, yes. For potential fans that know nothing about Transformers but want to give it a go? No. I'd recommend that they watch Tf: Prime first (or the live action movies since they would have already seen or heard of them). Then when they watch G1, they'll hopefully have a much better understanding and appreciation of what started it all.
Oh, by the way, I (Is hate too strong a word? Probably.) really dislike the events of the 1986 movie. Seriously, Galvatron? Yuck. So seasons 3 & 4 are ruined for me. Bring back Megatron, please.